Onchocerciasis Treatments
In 2008, 87.5 million treatments were approved for mass distribution of Mectizan for onchocerciasis. Since the program's inception in 1987, more than 300 million treatments have been approved.
The Treatment of Onchocerciasis
A single, annual dose of Mectizan™ of 150 to 200 µg/kg has been found to effectively reduce the microfilarial density in the skin to near zero after one month and to successfully maintain a low microfilarial level for up to 12 months. Reduction of microfilarial density in the skin can significantly reduce parasite transmission.1 At present, the specific mechanism of action of Mectizan against O. volvulus has not been clearly delineated. It has been determined that Mectizan has a direct toxic effect on microfilariae and also interferes with their development and release from the adult female worm uterus.1 Mectizan also has a very beneficial effect on symptoms and clinical manifestations due to onchocerciasis. It relieves the intense itching from the disease, and it clears microfilariae from the eye, thus halting the progression towards blindness except in very advanced cases.2,3
References
1. Goa KL, McTavish D, Clissold SP. Ivermectin, a review of its antifilarial activity, pharmacokinetic properties, and clinical efficacy in onchocerciasis. Drugs 1991;42(4):640-658.
2. World Health Organization. Onchocerciasis and its control, report of a WHO Expert Committee on Onchocerciasis Control. Geneva: World Health Organization; 1995. Technical Report Series No.: 852.
3. Ogbuagu KF, Eneanya CI. A multi-centre study of the effect of Mectizan treatment on onchocercal skin disease: clinical findings. Ann Trop Med Parasitol 1998;92(Suppl 1): 139-145.